Make and break or change-over electric switch



.1. ROBERTS 2,501,964

MAKE AND BREAK 0R CHANGE-OVER ELECTRIC SWITCH March 28, 1950 2Sheets-Sheet l Filed July 25, 1947 ,./HUIJIIITIQ @Iam 'am-am.

lll Lllullmm 2T'- 7 INVENTOR :L Z7 .i dof/V @negers /7 .id Zi ATTORNEYSMarch 2s, 1950 J. ROBERTS MAKE AND BREAK OR CHANGE-OVER ELECTRIC SWITCHFiled July 23, 1947 2 Sheets-Sheet 2 INVNTOR Jo/m/ 055,675'

'SYM 'LM/LM ATTORNEYS Patented Mar. 28, 1950 UNITED- STATES PATENTOFFICE MAKE AND BREAK OR CHANGE-OVER ELECTRC SWITCH John- Roberts,London, England 4 Claims. l

This invention relates to rotary electric fuseswitch combinations andhas for its chief object the provision oi an improved and simplifiedform of such a fuse-switch combination which is or". rugged constructionand is particularly adapted for use as a heavy duty electric fuse-switchin high-amperage circuits,

According to one feature of the present invention provision is made of arotary electric fuse-switch combination having a rotor which carrieselectrically conductive contact members adapted for bridging engagementwith and disengagement from two pairs of stationary electricallyconductive contact members, wherein one of each pair of the stationarycontact members is adapted to be connected in an electrical currentcircuit and the remaining contact members of the two pairs are adaptedto be bridged by a stationary fuse member,and wherein th rotary andstationary Contact members are relatively disposed so as to make andbreak the path of current at separate points which are located toopposite sides of the fuse member so that the latter is completelyisolated from the circuitconnecting contacts when the rotary switchcontacts are in the disengaged or open position.

According to another feature of the invention provision is made of arotary multi-pole electric iuse-switch combination having two pairs ofstationary electrically-conductive contact members embodied in eachpolev of the switch, each pair of said contacts being adapted to bebridged by a rotary electrically-conductive contact memer, to make orclose a circuit for one pole of an electrical current, whereinonecontact of each pair oi stationary contacts is adapted for'connection to a source of current and current load respectively and theother contacts of the two pairs are adapted to be electrically bridgedby a stationary fuse-member, the said rotary and sta'- tionary contactmembers being relatively disposed so as to make and break the path ofcurrent through the switch pole at two separate points which are locatedto opposite sides of the fuse member so that the latter is completelyisolated from the current-supply and current-load contacts of the switchwhen the rotary contacts are in the open or disengaged position.

In a form of the invention which is at present preferred the rotarycontact members may be mounted upon a switch rotor which comprises adisc or drum carrying the rotary contact members upon its peripheralsurface and the xed and rotary contacts are relatively disposed so as tomake and break the path of current at two i' points which are locatedupon diametrically op` posite sides of the switch rotor.

According to another feature of the invention the disc or drum when suchis used may be provided with an annular groove or plurality of annulargrooves in its peripheral surface and the' rotary contact members aredisposed upon the bottom of the groove or of each groove, so that thecontacts are contained between walls of insulating material.

According to another feature of the invention it may also be arranged sothat the contact members or strips carried by the switch rotor are letinto recesses formed in the surface of such rotor and are urgedoutwardly therefrom by resilient means, for example, spring means.

rlhe means for effecting angular movement of the switch rotor may takevarious forms one 0I" which comprises a rod` or projection orprojections disposed parallel with the axis of rotation of the switchrotor and caused to engage a slot therein so that by bodily displacementof the rod or projection or projections along an arcuate path the saidrotor will be angularly displaced to the desired extent. The rod orprojection or projections may be carried by or mounted in position uponone or more radially disposed rocker arms having resilient meansassociated therewith and arranged to impart a snap-over action to therocker arm or arms in the displacement of the rod or projection orprojections from one end to the other of the arcuate path of movementthereof.

Preferably, the slot or slots in the switch rotor in which the rod orprojection or each projection engages is or are made arcute andelongated sufficiently to provide a lost motion coupling between thesaid parts so that the angular movement of the said rotor is mainlyeiected by and is completed during the snap-over movement of the rockerarm or arms.

Conveniently, the radially disposed rocker arm or each of such arms mayhave helical spring means associated therewith and normally ten-l sionedand inclined to a radial line extending from the rod or projection tothe axis o rotation of the switch rotor so as yeldingly to hold the rodor projection at one end of the arcuate slot in which it is locatedthereby maintaining the rod and said rotor in one positiony of angulardisplacement. Such spring or springs may be conveniently arranged tobecome further tensioned and aligned with the said radial line when therod or projection is displaced toi the other end of its arcuate slot andto act, upon further 3 displacement of the rod or projection, tocomplete the movement of the latter and the said rotor to thealternative angular position oi displacement.

Furthermore, the switch rotor may be provided with an arcuate slot orslots in to which a iixed rod or projection or projections extends orextend to limit the angular displacement of the rotor to a dead beatmovement.

The invention is particularly applicable to multiphase e. g. threeephasecircuits and, as ap plied thereto, may be provided with a plurality saythree spaced and coaxially arranged switch rotor discs or drums eachhaving the characteristlcs out-lined and adapted to be displacedsimultaneously by a single rod extending through three aligned arcuateslots, viz. one in each of the discs or drums.

In order that the invention may be fully understood and carried intoeffect, a constructional embodiment thereof will hereinafter bedescribed, by way oi example, and without implied limitation byreference to the accompanying drawings in which- Figure 1 is a sideelevational View of a rotary triple pole fuse-switch mechanism with theswitch casing removed;

Figure 2 is a plan View thereof;

Figure 3 is a sectional View taken on line III-III of Fig. 2, showingthe switch contacts in the on position;

Figure 4 is a sectional view similar to Fig. 3, but showing the switchcontacts in the ofi position; and

Figures 5 and 6 are fragmentary detail views of the switch operatinghandle devices.

Referring to the drawings, I indicates rectangular side plates havingtheir rear ends flanged and drilled to provide brackets 2 for attachmentby screws 3 to the back of a switch casing 4 (shown in chain dot outlinein Fig. 1).

Front and rear pairs of rods 5, 6 extend between the side plates I, theends of the rods being screw-threaded and passed through holes in theplates to receive washers 1 and securing nuts 8.

The front pair of rods 5 are passed through the sides of threerectangular contact-mounting blocks 9, sp-acer sleeves l0, andlongitudinal insulating shields Ii, all of which are rigidly clampedtogether, with the blocks 3 and screens Il in parallel, spaced relation,when the nuts 8 are screwed down upon the ends of the rods 5. In asimilar manner, the inner rods E are passed through three arcuatecontact-mounting blocks I2, and spacer sleeves I 3 which are clampedtightp ly together with the blocks I2 held in parallel spaced relation,when the nuts are screwed down upon the ends of rods 6. The middle rearportions of the shields il are cut away to leave a clearance -betweenthe rear parts of the plates l.

The contact-mounting blocks 9, l2 and the associated spacer sleeves Il),i3 are all made of electrical insulating material or, at least, mainlycomposed of such material.

A spindle I1 is also extended between the side vplates I, intermediatethe front and rear rods 5, E, the ends of the spindle being journalledin, and projecting outwards from, the plates4 Upon spindle I1 arerotatably mounted three contact carrying discs or drums Ill providedwith comparatively wide peripheral flanges I9 and axial bosses or hubs20, which latter abut to act as spacers between the adjacent drums andbetween the outer drums and adjacent side plates. The drums I8, whichconstitute the switch rotor may be made as an integral whole, or builtup from two or more parts, and are preferably metal bushed.

The drums I8 are free to rotate about spindle I1y but are limited to arocking movement by a rod 2l which is xedly secured at its ends to theside plates I, and extends therebetween as shown in Fig. 1. The rod 2lpasses through arcuate slots 22 which are formed in the drums IB, theslots 22 being concentric with the axis of rotation of the drums, anddisposed in axial alignment with their sides parallel to the spindle I1.

A second set oi arcuate slots 23, which are mutually aligned anddisposed similarly to the slots 22 in relation to the spindle I1, butmore or less diametrically opposite to the slots 22, are formed in thedrums I8. A drum rocking rod 24 extends through the slots 23, the endsof the rod 24 passing freely through arcuate slots 25 which are formedin the plates I, concentric with the axis of spindle I1. The outer endsof the rod 24 enter blind roles 26 formed in the inner faces of rockerarms 21 which are mounted upon and pinned to the outwardly projectingends of spindle I1, the rocker arms thus being locked together forsimultaneous and equal movement. Spring-anchoring pins 28 are securedto, and project outwards from, the free extremities of the rocker arms21, and similar pins 29 are secured to, and project outwards from, theside plates I in parallel relation to the pins 28. The pins 29 arelocated in a plane containing the axis of the spindle I1 and the centresof curvature of the arcuate slots 25 in the side plates I. Helicaltension springs 30 are anchored between each pair of pins 28, 29 and arenormally tensioned to hold the rocker arms 21 to one side or the otherof the axial plane referred to above.

Arcuate recesses 3| are formed in diametrically opposite parts of theperipheral surface of each drum I8, and convex contact strips 32 ofcopper,

brass or other electrically conductive material are inserted in therecesses 3|. Blade springs 33, interposed between the contact strips 32and convex bottom surfaces of the recesses 3l, act rer siliently todisplace the contact strips outwards from the recesses 3I to a limitedextent, as shown in Figs. 3 and 4.

Pairs of electrically conductive stationary contacts, which may besuitably formed, for example, of square section brass rod, are securedto the ends of the contact-mounting blocks 9. Each contact comprises acontact bar I5 carried by, and formed integral with, a post I4 which issecured to the block 9 by cheese head screws 34 which pass through theposts I4 and engage drilled and tapped metal inserts 35 set in the endsof the blocks 9.

Contact bars 36, also of square sectional metal such as brass, aresecured to the flat ends of the arcuate contact mounting blocks I2 bycheese head screws 39 which engage drilled and tapped metal inserts setin the ends of the blocks. The contact bars 36 are provided with sockets31 and set screws 38 to form terminal connections for electrical leads(not shown).

The contact bars I5, 36 are radial to the longitudinal axis of the drumsI8, and extend inwards towards the drum to bring the inner ends of thestationary contact bars, which are made appropriately concave, intosubstantially full surface contact with the outer convex surfaces of therotary contact strips 32. In the arrangement shown in the drawings onerotary contact strip 32 remains constantly in engagement with one of thenxed stationary contact bars I5 while the other rotary contact stripremains constantly in engagement with one of the iixed stationarycontact bars 36.

The fixed contact bars I5 vare-electrically bridged by stationarycartridge fuse elements 48 which are provided with metallic connectingbrackets or lugs 42; the fuse brackets being secured to the contactposts I4 by cheese head screws 4I which engage in drilled and tappedholes in the ends of the posts.

The above described mechanism when in use will be housed in a metalcasing 4 complete with a removable cover (not shown) and willbe'actuated by a switch arm and handle 43 (Figs. 5 and 6) pivotallymounted upon the other side of the casing 4 and connected to a rockerpin 41 upon which is mounted a pin plate 45 set within the casing 4 andcarrying a pair of shift pins 46 projecting therefrom for engagementwith one of the rocker arms 21.

The insulating screens II have transverse insulating shields 44associated therewith so that each set of contact bars I5, 36 is shieldedfrom the adjacent set or sets of contact bars by a longitudinal shieldH, and the contact bars of each pair between which Contact is made andbroken by the displaceable contacts, are shielded one from the other bytransverse shields 44. It will be noted also that the contact ends ofthe respective pairs of contacts are shielded one from the other by therelative disposition thereof upon opposite sides of the drums, and arealso shielded from the adjacent sets of contacts by the radiallyprojecting flanges I9 of the drums I8.

In the operation of the switch mechanism above described, assuming thatthe switch is connected in an electrical circuit by leads secured in theterminal sockets 31 and that the rotary switch contacts are in the breakor ofi position shown in Fig. 4, by manipulation of the switch handle43, the shift 'pin 46 will be caused to shift the rocker arms 21 fromthe position corresponding to that shown in Fig. 4 towards the positioncorresponding to that shown in Fig. 3. In the ilrst part of thismovement the rocker arms are moved against the tension of the springs 30which thus become further tensioned and aligned with a radial lineextending from axial centres of the rod 24 and pins 28 to the axis ofthe drums I8 and spindle I1. During this part of the movement of therocker arms the rod 24 is displaced to the further ends of the arcuateslots 23 without moving the drums switch rotor I3. By further rockingmovement of the arms 21 the tensioned springs 3G are carried past thedead centre position, and the movement oi the rocker arms 21 and rod 24to the position shown in Fig. 3 is rapidly completed by contraction ofthe springs in a so-called spring-snap action. In the last part of themovement of rod 24 it carries the drums I8 round with it, and eachrotary contact strip 32 rapidly moves towards, and slides into contactwith, the opposite member of the make and break pair of fixed contactsI5, 35 with which it is associated, so that the gap between the saidiixed contacts is bridged by the rotary contact strip. Thus, the circuitof each pole is completed over fixed terminal contacts 36, bridgingcontact strips 32, xed contacts I4, I5 and bridging fuse 43.

Manipulation of the switch handle 43 to eiect reverse movements of thedisplaceable drums and contacts with the lost motion spring-loadedcoupling between the drums I8 and rod 24 will also serve to eiiect rapidor snap-action break between, the fixed andl rotary contact members. Itwill be realised that each pole of .the switch is thus lbroken orinterrupted at two points which lie respectively to eitherr side of the-fuse member incorporated therein so that the latter is: completelyvisolated fromy the switch terminals 3T, i. e. the electrically aliveside ofk the switch, when the switch contacts are open or in ther breakposition.

It will be obvious that in a modification. of the above describedrconstructional embodiment of the invention, the several discs or drumsI8 may, if desired, be'made integral in the form of an elongatedmulti-grooved, cylindrical drum.y

I claim.:

1. A rotary electric. fuse-switch comprising a support, a rotor mountedrotatably in the support, means for rotating the rotor, two pairs ofrigidly mounted rigid contact blocks located around and adjacent therotor and in a common plane therewith, stationary fuse-holding meansconnected to one pair of said blocks, means for connecting the otherpair of blocks across a break in an electric current line, two contactmembers having outer convex surfaces operatively movable with andcarried by the said rotor, springs carried by said rotor for urging saidcontact members radially outwardly from the axis of the rotor to engagethe contact blocks in radial directions, said contact members beingadapted to such engagement to connect a fuse-connected block with alineconnected block on one side of the fuse and the other fuse-connectedblock with the other lineconnected block on the other side of the fuse,said rotor being rotatable to an off position.

2. A rotary electric fuse-switch comprising a support, an insulatorrotor mounted rotatably in the support, means for rotating the rotor, astationary fuse-carrying insulator block mounted on one side of therotor, a stationary electric line terminal-carrying insulator blockmounted on the opposite side of the rotor, a pair of rigid fuse contactblocks attached to opposite ends of the fuse-carrying block andextending on opposite sides thereof the extending ends on one side beingadjacent to the rotor, and the extending parts on the other side beingadapted for attachment thereto of a fuse for bridging these blocks,fusecarrying means directly attached to said parts, a pair of rigid lineterminal contact blocks mounted at opposite ends of the terminalcarrying insulator block and projecting on opposite sides thereof theprojecting ends on one side being in proximity to the rotor and in thesame plane as the fuse contact blocks and the other projecting endsbeing adapted for direct attachment thereto of the electric line, twocontact elements having outer convex surfaces operatively movable withand carried by the rotor, springs carried by the rotor for resilientlyurging said contact elements radially away from the rotor so as to bepressed rmly into contact with the contact blocks so as to connect thefuse-connected block on one side of the fuse with a line-connected blockand the other fuse-connected block with the other line-connected blockon the other side of the fuse, said rotor being rotatable to an oiposition.

3. A rotary electric fuse-switch combination as claimed in claim 1,wherein the rotor is freely mounted on a spindle fixed in the support,said rotor having an arcuate slot therein, a rod disposed parallel tothe said spindle and disposed in the slot of said rotor to engage thesame so that by bodily displacement of the rod along an arcuate path thesaid rotor will be angularly displaced, a rocker arm carrying the rod,resilient means associated with the rod and arranged to impart asnap-over action to the rocker arm upon displacement of the rod, saidslot providing a lost motion coupling between the rotor and the rod sothat the angular movement of the switch rotor is mainly eiected by andis completed during the snap-over movement of the rocker arm.

4. A rotary electric fuse-switch combination as claimed in claim 1,wherein the means for rotating the rotor comprises means for engagingsaid rotor, and resilient means associated with said engaging means andarranged to impart a snapover action thereto, said rotor being cut awayto provide a lost motion coupling between said rotor REFERENCES CITEDThe following references are of record in the le of this patent:

UNITED STATES PATENTS Number Name Date 1,224,119 Sutherland Apr. 24,1917 1,678,336 Getchell July 24, 1928 2,002,587 Sachs May 28, 1935

